But the new service should still be affordable, even for many rural Indians. The average monthly income is $160.

This is Facebook's second attempt to bring millions of Indians online.

The first, through a program called Free Basics, was blocked by Indian officials last year after internet activists in the country said it would break net neutrality rules aimed at preventing companies favoring certain websites or apps on their networks.

India is the fifth country to get Express Wi-Fi after Kenya, Tanzania, Nigeria and Indonesia but by far the biggest in terms of potential users. Only about 400 million of its 1.3 billion people currently have access to the internet.

The world's biggest technology firms are racing to bring them online and capture a huge market in the process.